Heritable disorders affect many domestic species, including the horse. In the Arabian breed of horse a neurological disorder has been reported that is lethal soon after birth [Bowling A T (1996) Medical Genetics. Horse Genetics. Wallingford, UK: CABI International. pp. 105-106]. Affected foals can display an array of neurological signs including tetanic-like seizures, opisthotonus, stiff or paddling leg movements and nystagmus [Fanelli H H (2005) Coat colour dilution lethal (‘lavender foal syndrome’): a tetany syndrome of Arabian foals. Equine Veterinary Education 17: 260-263.]. Mild leucopenia is sometimes observed [Fanelli H H (2005), and Page P, Parker R, Harper C, Guthrie A, Neser J (2006) Clinical, clinicopathologic, postmortem examination findings and familial history of 3 Arabians with lavender foal syndrome. J Vet Intern Med 20: 1491-1494]. These neurologic impairments prevent the foal from standing and nursing normally and, if not lethal on their own, are often cause for euthanasia. In addition to these abnormalities, affected foals possess a characteristic diluted “lavender” coat color. This resulting coat color, variously described as pale gray, pewter, and light chestnut, as well as lavender, has coined the name “Lavender Foal Syndrome” (LFS) [Fanelli H H (2005)]. Also called “Coat Color Dilution Lethal” [Fanelli H H (2005)]. There is currently no treatment for LFS available. Additionally, initial diagnosis can be difficult as the clinical signs of LFS can easily be confused with a number of neonatal conditions including neonatal maladjustment syndrome and encephalitis [Fanelli H H (2005)]. Thus, there is an ongoing and unmet need provide improved methods for diagnosis of LFS. The present invention meets this and other needs.